Apparatus for burning fine fuel in suspension



Sept. 11, 1928.

J. POLLOCK APPARATUS FOR BURNING FINE FUEL IN SUSPENSION Filed Sept. 15, 1926 Patented Sept. 11, 1928. r

JAMES POLLOCK, OF YORK, N. Y.

APPARATUS FOR BURNING FINE FUEL IN SUSPENSION.

Application filed September 13, 1926. Serial Nof135,222.

This" invention relates to furnaces for burning fine fuel, such as coal dust, in suspension. In my Patent No. 1,530,321, dated March 17, 1925, I have shown a furnace of this type in which air and fuel are blown upwardly in anupwardlyenlarging combustion chamber, and the fuel is held in suspen sion until consumed. The fuel is ignited by oil burners, but after the furnace has become well heated the burners are extinguished and the fresh fuel blown m'ingles with. the incandescent fuel already in the chamber and is ignited and consumed. To promote combustion, air is admitted at various points in the height of the furnace.

the pressure and volume of air being controlled so as to supply what air is needed for 'complete combustion without causing such an increase in pressure as would force unburned fuel particles out at the top of the chamber.

It is found to be of very material advan tage, in this type of furnace, to preheat the air admitted to the combustion chamber, because cold air blown in tends to chill the fine incandescent particles of fuel and to hinder combustion. In the present invention, there fore, I have provided a preheater for the air, arranged in the furnace stack so as to utilize the heat in the stack which would otherwise be wasted, and this preheated air is blown into the furnace chamber, thus avoiding the chilling effect of cold air on the incandescent fuel and conserving a considerable amount of heat energy.

It is important in this type of furnace to retain the fine fuel in the furnace chamber until consumed, and therefore it is desirable not only to avoid such internal pressure in the chamber as would force unconsumed par ticles out at the top, but it is necessary to avoid having a relatively low pressure in the flue leading to the stack, as this would have the same effect. In my Patent No. 1,606,719 dated November 9, 1926, I have shown a fur-- nace with a stack which is relatively short in order not to create a strong draft, and means for regulating the flow of gases to the stack, so as to retain a balanced pressure in the furnace chamber. The draft through the stack is influenced by the wind blowing past the stack, and also by barometric pressure. I have, therefore, in the present invention, arranged a damper at the outlet of the stack, to adjust the size of the outlet, and also a wind shield which is adjustable with the into the chamber damper and surrounds the opening to prevent the draft from being affected by changing atmospheric conditions.

' In the accompanying drawing,

Fig. l is a longitudinal central section through the furnace, and,

Fig. 2 is a central vertical section through the stack and air heater, partly broken away and on a larger scale than is shown in Fig. 1.

Referring to the drawing, a indicates a combustion chamber of thevkind shown in my prior patent, this chamber enlarging gradually from the bottom to the top, and I; indicates a flue leading downwardly from the top of the combustion chamber into a chamber 0, containing a tubular boiler d, and the chamber 0 communicates through pas partly broken away sageway 6 with a relatively short cylindrical stack f. lVithin the stack is arranged a preheater 9, for preheating the air which is supplied to the furnace. A fan h is shown for forcing air into the upper end of the preheater through a pipe 1,;and from the lower end of the preheater a pipe 2 extends to a "point adjacent the furnace chamber a. A pipe 3 extends from the pipe 2 to a nozzle 4., arranged at the lower end of the furnace chamber and adapted to. direct the "air upwardly in said chamber. Several branch pipes 5, 6 and 7 are shown connected to the pipe 2 and opening into the furnace chamber at various points in the height of the latter. Fine fuel is fed to the nozzle 4 through a pipe 8, by suitable feed mechanlsm, the details of which are not shown. As 1n my former patent, oil or gas burners are arranged in the lower part of the furnace chamber for initially igniting the fuel, one of these burners being indicated at 9, Fig. 1.

The preheater 9" comprises two hollow circular drums or heads 10 and 11, and the pipes 1 and 2 communicate with these heads, respectively. The heads are connected together by tubes 12, through which the air may pass from one head to another. These lUl) tubes fit within the casing of the stack 7,

14 on the lower part of the stack, and the lower ends of, the reds are threaded and provided with nuts 15, by which $1M;v IjQdsv which the gases flow will be restricted, and, v

by adjusting the damper downwardly the width of the ap willbe increased to perigit a freer flow 0? the gases. Byiegulatin'gft e vo me d P ssu e f r dmitte to he furnace 'chamb erfand reg lating' the widthbf the gap is, the pressure in the furnace chamber may be balanced s9 that, the f el pr je d 'wa idli' hl'm g h zz Wi1I hld in i p nslon 1 ,61 en r la consumed. h

As the, draft through the stack wculd be the tpp of the chamber iwitht e low part of; the stack, an air heateiiin t e sta havingahhollow head extending over the stack and spacedjfrgm the same; leaving an an- 1111? gap for' tli escape of gases, an annu- 4 Mar. am er sli a I, u on the stack V for"vai?ing"' hii i vidtl i bu said gap, and n e ans '1' through the heater 1nt0 the urnace c r.

2- n a appar tus fie ham ngl ne fu suspeasie a f aaa hamhsr, a ele: vel 1 w ate k. and passaeeweysiwnn ctine h we at h ebamba iw t ftha sw r pm. 9f theist s ky an a' heater iath steels av a 9 1%? been a teningtoxe th Steels 4 1 149 1 free the awakening e ar ea fer t wer oilgesea anzaimulan e t d y WW wi Over the of eeper 11 4b? v t cally" 11 .91 the stack: mlfl h gal I av er-marke fibe-w d het e d ames S 1 proyided an annular windshie d m, which is secured to thedamper but spaced from it,

as shown, and pio e ct-s above the. {r seed also above the header l0i when e 7 h I ,fi p' r is'pa ly it isedhe w qifinbt ow h ek- I str n Win pi v fir n i ld m y b'cith, be raised st as to lower the aspirating fifl i big h j wi d abl w n Y he t p ofthe stack, and'when the weather is calm, the shield 'and' dan pe'r be lowered to pe i j e e o flow 1 mo e f ee y y h'li t' a1*p s ui e her fl w Q g se h 'w th i k p t t q pherew s al o afiectedby barbmetric pressure; the damper 'niay raisedbr lowered to compensate for a to hefumaeec am e h h e's x fltme rh im i ze is re- W a -I time: Ii a rams in ensign, alf urna ce chamber, a relaiY-e fi' l f e' lsia s passa eway qlapectins nu a w 16 o arge 'd a etan an the damper se med t9 the dampex sl' PM. Jeeves ab v he same said shield; bei m able w l h am :Ql'aand: mean e am n ai h eugh't .94 heater.- i te the rm chem e 3-1 an aigp mt s trimmin eet a. rna hea e11, paid passagew ys Connecting e hamber with t e 19m. m,- f s a k, n e aheeter .1 he eels ing a hollow head extending over the staph d pa d. i em es m i l a ina enuna i ap fos e a ap gases, eai imulaa ampen sliqeb e Yet a. mew; t e. tud: e t r gime; the w dthv at sa d: gap, and: mew q 1M1. thwash the.

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